Hydraulic pump or motor



June 15, 1965 R. w, BRUNDAGE 3,188,969 HYDRAULIC PUMP 0R MoToR l 2 Sheets-Sheet l Original Filed Sept. 6, 1957 ATTORNEY June 15, 1965 R. w. BRUNDAGE HYDRAULIC PUMP OR MOTOR Original Filed Sept. 6, 1957 2 Sheets-Sheet 2 les INVENTOR. ROBERT w. BRUNDAGE ATTORNEY United States Patent O 3,188,969 HYDRAULIC PUMP R MOTOR Robert W. Brundage, 2809 Wakonda Drive, Belnor, St. Louis 21, Mo.

Original application Sept. 6, 1957, Ser. No. 682,501, now Patent No. 3,034,446, dated May 15, 1962. Divided and this application Feb. 26, 1962, Ser. No. 175,722

2 Claims. (Cl. 103-126) This application is a division of application Serial No. 682,501, filed September 6, 1957, now United States Letters Patent No. 3,034,446.

- This invention pertains to the art of hydraulic pumps or motors and more particularly to a hydraulic pump or motor of the positive displacement type yintended for high pressure and high eiciency applications.

The invention is particularly applicable to a hydraulic pump of the internal gear type and will be described with particular reference thereto, although it will be appreciated that the invention, or at least portions thereof, is equally applicable to other types of hydraulic pumps or motors. In a pump, high and low pressures correspond to discharge and inlet pressures. If the invention is to be considered in relation to a motor, such high and low pressures will then become the inlet and discharge pressures.

Hydraulic pumps of the type to which this invention pertains are normally'comprised of a housing, a shaft extending into the housing and rotatably supported therein in suitable bearings. A plurality of members, such as intermeshed, internally-toothed and externally-toothed gears, rotate with the shaft in a bearing surface eccentric to the axis of the shaft to define a plurality of increasing and decreasing volume pumping chambers. Inlet and outlet manifolds communicating with these chambers are formed in the housing.

In these high pressure pumps, the high pressure in the chambers is on one side of the shaft only. The mechanical forces created by such pressures are unsymmetrical and must be transmitted through the shaft and its supporting bearings to the housing. Because of the size of the forces, it has heretofore been conventional to support the shaft in either roll or ball bearings of the precision type which are not only very expensive, but are also relatively bulky.

The present invention contemplates a new and improved hydraulic pump or motor, hereinafter generally referred to as a hydraulic device, of the general type described which overcomes all of the above referred to diftculties and others, and provides a high efficiency, high pressure positive displacement hydraulic device which is simple in construction, is very economical to manufacture, has a maximum useful life and has high hydraulic and mechanical efficiency throughout its life.

In accordance with the present invention, a hydraulic device of the general type described is provided wherein the shaft supporting bearings are in the form of conventional sleeve bearings with portions of the bearing surfaces being recessed and communicated with the high pressure and other portions communicated with low pressure, the recessed portion being so proportioned in area and so circumferentially positioned that the high pressures therein exert hydraulic forces on the shaft generally equal and opposite to the hydraulic forces on the shaft created by the high pressures in the pumping chambers. With this arrangement, the shaft in effect is hydraulically floated, and relatively cheap bearing members may be employed as distinguished from the roller or ball bearings heretofore employed.

The principal object of the invention is the provision of a new and improved hydraulic device of the general 3,188,969 Patented June 15, 1965 type described which is economical to manufacture, and which has a high mechanical and hydraulic efficiency.

Another object of the invention is the provision of a new and improved hydraulic device, including a rotating shaft member wherein the shaft is in effect hydraulically floated in the pump housing.

Another object of the invention is the provision of a new and improved arrangement for journaling the shaft of a hydraulic pump having substantial radial forces thereon which includes exposing portions of the shaft to the high pressures whereby to create equal and opposite radial forces thereon.

The invention may take physical form in certain parts and arrangement of parts, preferred embodiments of which will be described in detail in this specification and illustrated in the accompanying drawing which is a part hereof and wherein: s

FIG. l is a cross-sectional view perpendicular to the neutral axis of a hydraulic device illustrating a preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of FIG. 1 taken partially on the line 2-2 and partially on the line 2a2a;

FIG. 3 is a perspective plan layout of the eccentric Img;

FIG. 4 is a cross-sectional view of FIG. 1 taken approximately on the line 4-4 thereof; and

FIG. 5 is a perspective plan layout of the shaft bearmg.

Referring now to the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purposes of limiting same, the figures show a pump including a housing 10 having generally cylindrical side walls 11 and a pair of end walls 12, 13, all dening a closed cavity 14. A shaft 15 coaxial with the side walls 11 extends through the end wall 12 and is supported for rotation in a bearing sleeve 16, in turn, mounted in the right end wall 13.

Immediately adjacent the end wall 13, an externallytoothed gear 17 is mounted for rotation with the shaft 15 by means of a key 9 in a keyway 8. This gear is in turn surrounded by and intermeshed with the teeth of an internally-toothed gear 18 supported for rotation in a ring 19 having an inner surface 20 eccentric to the outer surface 21.

The gear 18 may have one or more teeth than the gear 17 and is mounted for rotation on an axis 18' eccentric to the axis 15 of the shaft 15 so as to define a plurality of increasing and decreasing volume chambers 22, 23, separated by what may be termed a neutral axis 24 passing through the points of chamber minimum and maxiymum volume 25, 26 respectively.

The end Wall 13 is in sealing engagement with the sides of the gears 17, 18 and is provided with arcuately extending inlet and discharge manifolds 30, 31 separated by stops or lands 32 and in turn communicating with inlet and outlet ports 33, 34 threaded to receive pipe fittings, not shown.

The inlet and outlet manifolds 30, 31 as shown, have a substantial arcuate extent, and are continuously incommunication with the increasing or decreasing volume chambers 22, 23 as the case may be. These manifolds increase slightly in radial width toward the maximum volume point 26.

A sealing disc 36, both rotatably supports the shaft 15 and is axially movable relative thereto to bear against the left hand side of the gears 17, 18 to close this axial end of the chambers 22, 23. The sealing disc 36 has a cylindrical portion 50 which surrounds the shaft 15 and extends into an opening 41 in the end wall 12. Pliable sealing means in the form of an O-ring 43 positioned in a'groove 44 inthe cylindrical portion 40 rcloses the opening 41.

A pin 45 extends axially through anY opening 47 in the eccentric ring 19 into an opening 46 in the end wall13 disc 36. This pin locates the eccentricity of the' ring l19 with the piece of the housinghaving the inlet and outletl manifolds' therein and is an important part ofthe present invention.. *The pin incidentally holds the disc 36' against rotation. A passagev 37 inthe face of thek disc 36 communicates the-cavity"14 with the high pressure chamber 23. This high pressure exerts a force A. against a pressure surface 38fon the sealing'dis'c 36 remote from the gears"17,`18 so a's toV continuously urge Vthe sealingY disc 36 into sealing engagement with the gears.V

The hydraulic pressures in'the decreasing volume' chambers23' exert an unsymme'tric'all radial force C land and a notch-48 in the outer periphery of thesealingv l in the shaft supporting surface of the disc 36 are idenvtical'to that of the bearing sleeve 16, and will not be described further herein. Y The unbalanced radial force C on the inner surface of the outer ring gear is almost totally opposed by an almost Vequal and opposite unsymmetrical Vradial force on the Youter surface thereof. In accordance with the invention,

thisis accomplished by'providing the inner bearing sur- "1 face 2,0 of the sealing ring 19 with a low pressure recess 8:3 boundedon each axial'side by lands S4 and on the circumferential ends vby lands V85, 86. The circumferential widthof the recess andthe lands 85, 86 is preferably equal to Vor less than 180'. The recess 83 may be e communicated with the low pressureV in any desired manner, but in the'preferred embodiment a'. radial passage 87 extends to the outer surface: of the sealing ring 19 C on the axial center of gears 1'7,`;18 respectively`. This Y force Con the, gear 17 is transmitted to* the shaftv 15 and. thence toY the-housing.. throughboth-the bearing 16` and the sealing disc 36. The force between bearingk V16 and the shaft 15 is indicatediby the' radial force E on the axial center of the' bearing'su'rf1acesand the' force be` tween the sealing disc 36A and the' shaft. 15 is indicated yby the radial force'. Fon theaxialcenterof. the' bearingY surfaces, and Ithe' forcebetween the sealing disc 36v and the housing10isindicatedby the radiali force G.. Y p

The forces E and F in a high .pressure hydraulic pump are very substantial forces which wouldy normally rfequire the use of. expensive'roller or ball bearingsv if maximumA wear isA to:v be obtained..f In accordancev with the present invention,.however, the shaft 15 is inV elfect hy-J draulically floated inthe bearing 16' and the sealing disc` Thus the bearingr sleeifev 16 (see 5 lia-sa recessv 55 f on its inwardly facing surface communicated with. .the high pressures throughs. radial opening 56I in the sleeve 16, an annular groove 57 in the end wall.13.and ariopen'.-

ing 58 leadingto the .high pressure outlet port 34'.V This.

thigh pressure recess 55'is closed in-on each-axial' side `by a land 60,v and lon' eachcircumferential end by.y lands-63,1 64 all kof which are insealing contact with'. thevv surfface, of theshaft 15..- :The inner surface of the bearing sleeve 16`is ,also provided with a" pair of; lowpressurev recesses 65, 66 separated from. each` other by a land 67, and from rthe high pressurerecess 55 b y meansof the lands 63,'l64respectively. The low pressure recesses 65,

to the right or'low pressure end ofapliable sealing member in form .of :an O-ring 88V positioned in a circumferjentially extending groove. 89 jin the4 outer` surface of the eccentric ring` 19. A back-,up washer 90is provided to prevent'the high pressure in the vcavity 14 forcing the pliable ring 8.8 between the outer surface of the ring 19 and the inner surface of the housing 11.- The :space to the right ofthe packing ring `I8 is com municated with the -inlet p ort33 bymeans pcf,n an axially.

extending passage 91 formed in the end well 13.

The bearing surface 20 also hasy formed therein high pressure recesses 80, 81 of a total 180 circumferential width separated from eachother byay land 82 and from the low pressure recess 83 by thelands 85, 86. These recesses 80, 81 extend they full axial Alength of the surface 20 and thuscommunicate with the. high pressure in the cavity 14. n vilt; is., to be noted `that the high pressure in the cavity14 holds the'eccentricnring member 19 in sealing ,engagement with the left handk .surface of the member'l, H .L

The high pressures inthe recesses 80, l81' exert an unsymmetrical radially inward force H- on the outer surface 66 extend axially the full length of the bearing sleeve 16,., y.

and are communicated with the low pressure -by means of a radial opening; 68y inthe vsleeve 16a lcircumferentiallyVV extending groove 6,9 surrounding the sleeve, a passage 61( to the inletport 33. Y Then land ,67 engagesthefsurface of the shaft 67 and preventsy it fromV moving radially in the bearing when the shaftis vstarted'i'n rotation.

Theq circumferential width of the recessl 55 alonev or takenwith the lands 63; 64i's. preferably less than 180",Y and the Aeiniumferential` midpoint l'is diametrically opposite to the' high pressure chamber midpoint. There cess 55 has a radially facing area' such that the rhydraulic pressure thereinr` exertsl a force opposite'` to' the force E and `just slightly less thanI such force so that the shaft v 15 rubs against the lands 63, 6,4 with a slight pressure to seal the highV pressure inthe recess V55 frorr'rthev low pressure recesses 65, 66.

The shaft 15 is'also ]ournaled inside the sealing disc 36 and its shaft facingisurface' is formed substantiallyA identical to a ,bearing sleeve 16; thus* the bearing surface of the ring gear 18,` Thesiz'e of this force' maybevaried by changing the size of the low pressure recess' 83 inthe course of design ormanufacture, and in accordance with the invention, thevareafof the lou/,pressure recess 83 is so formed that the force H will be s lightlyjgreater than thel force Cf so thatY the `outer surface of the `ring gear 18 will be held in sealing `engagement with the 'lands 85, 86 to thus prevent leakage Vbetweenthe high and low pressure areasof thefbear-ing surface 20. j t j Itwill thus b e seenthat an embodiment of the invention has been described which accomplishes all of the objects heretofore set` forthfand others to provide a hydraulic pump which maybe manufacturedat a minimum cost, whichwill have a highjeiciency, which is simple in conv struction, which will have Aa long useful life.

It will be appreciated that modificationsand alterations will occurl toV others uponl a reading and understanding of this specication, and it is my intention t'o include all such modificaticmsv and= alterationsinsofar as they come within the scope` of the present invention. In

` particular, it will be apprecited that the pump ycould be of the Vsealing disc 36 has a high pressure recess 79' v communicated with the cavity 14l through a radial passage 71, and surrounded on each axial side by lands 72,'l and on each circumferential side by lands 73, 74. Low pressure recesses 75, 76 are lseparatedby a land 77 and' communicate with recesses 65, 66 which are'at low pressure,

throughkeyway. Y Y

The' function, location and dimensionsy of the recesses designed .with la radial-dischargel other thainvaxial as shown. Further, it willr be appreciated that many of the features d'escribed'hereinA are equallyV applicable to vane type devi-ces, while some offrthe vfeatures described here- Yin are applicable to any type of hydraulic device.

' Having-thus described my invention, I claim:

1. Ahydraulic device comprised kof a housing, a single shaft rotatablyy supported in said .housing in a pair of said bearings to said housing, the improvement which comprises said bearings being in the form of a sleeve having a shaft facing inner surface, portions of said inner surfa-ce being in sealing engagement with said shaft and other portions of said inner surface being radially spaced therefrom to dene, with the inner surface of the sleeve, a high pressure recess and a low pressure recess circumferentially spaced from each other around the sleeve and sealed from each other by the sealing portions on the sleeve, means communicating said high and low pressure recesses respectively to high and low pressure areas of the device, said high pressure recess being located on the side of said shaft diametrically opposite from said chambers containing high pressure uid thereby creating a |hydraulic force on said shaft opposite to said first-mentioned hydraulic force, said low pressure recess extending arcuately for at least 180 and being positioned on the diametrically opposite side of said shaft from said chambers containing low pressure iluid, said high pressure recess having an arcuate extent less than 180 whereby the sealing portions engaging said shaft on each circumferential end of said high pressure recess lare located on the side of the shaft remote from the high pressure chambers, said high pressure recess having an area such References Cited hy the Examiner UNITED STATES PATENTS 1,372,576 3/21 Tullmann 103--126 1,379,587 5/21 Fisher 103-126 1,970,146 8/34 Hill 103-126 2,076,664 4/37 Nichols 103-126 2,319,374 5/43 Ungar 103-126 2,746,394 5/56 Dolza et al. 103-126 2,955,536 10/ 60 Gaubatz 103-126 3,034,446 5/62 Brundage 10S-126 JOSEPH H. BRANSON, JR., Prz'may Examiner. WILBUR I. GOODLIN, Examiner. 

1. A HYDRAULIC DEVICE COMPRISED OF A HOUSING, A SINGLE SHAFT ROTATABLY SUPPORTED IN SAID HOUSING IN A PAIR OF SPACED BEARINGS, CARRIED BY SAID HOUSING, A PLURALITY OF MEMBERS ROTATABLE WITH SAID SINGLE SHAFT AND POSITIONED BETWEEN SAID BEARINGS, SAID MEMBERS DEFINING A PLURALITY OF CHAMBERS WHICH INCREASE AND DECREASE IN VOLUME AS THE SHAFT ROTATES, SOME OF SAID CHAMBERS CONTAINING HYDRAULIC FLIID AT A HIGH PRESSURE THEREBY CREATING AN UNSYMMETRICAL RADIAL FORCE WHICH IS TRANSMITTED TO SAID SHAFT AND FROM SAID SHAFT TO SAID BEARINGS AND THEN FROM SAID BEARINGS TO SAID HOUSING, THE IMPROVEMENT WHICH COMPRISES SAID BEARINGS BEING IN THE FORM OF A SLEEVE HAVING A SHAFT FACING INNER SURFACE, PORTIONS OF SAID INNER SURFACE BEING IN SEALING ENGAGEMENT WITH SAID SHAFT AND OTHER PORTIONS OF SAID INNER SURFACE BEING RADIALLY SPACED THEREFROM TO DEFINE, WITH THE INNER SURFACE OF THE SLEEVE, A HIGH PRESSURE RECESS AND A LOW PRESSURE RECESS CIRCUMFERENTIALLY SPACED FROM EACH OTHER AROUND THE SLEEVE AND SEALED FROM EACH OTHER BY THE SEALING PORTIONS ON THE SLEEVE, MEANS COMMUNICATING SAID HIGH AND LOW PRESSURE RECESSES RESPECTIVELY TO HIGH AND LOW PRESSURE AREAS OF THE DEVICE, SAID HIGH PRESSURE RECESS BEING LOCATED ON THE SIDE OF SAID SHAFT DIAMETRICALLY OPPOSITE FROM SAID CHAMBERS CONTAINING HIGH PRESSURE FLUID THEREBY CREATING A HYDRAULIC FORCE ON SAID SHAFT OPPOSITE TO SAID FIRST-MENTIONED HYDRAULIC FORCE, SAID LOW PRESSURE RECESS EXTEND- 